A release device is meant to be a device that starts an extinguishing operation in the case of a fire. This necessitates detectors that contain sensors or elements that detect a fire parameter and generate a signal for signaling, switching and control purposes, in particular for releasing an extinguishing device. Fire parameters are understood to be variables that are linked to the start or the spreading of a fire such as e.g. temperature, smoke, radiation, gas emissions and thermal decomposition products.
To release an extinguishing agent as a rule also necessitates valves that release the flow of the extinguishing agent to the place of the fire in the case of a fire.
The inventive solution can be used wherever a signal is to be generated at a defined temperature after a change in temperature for signaling, switching and/or control purposes and where no electric energy is available from a battery, a rechargeable battery or another power supply or is not available reliably or constantly. This can be the case for example with extinguishing devices such as extinguishing systems or devices for storing an extinguishing agent like a fire extinguisher, that is to be released by an energy-independent release device, or by other autonomous systems for monitoring. In this way an area that is at risk of fire can be monitored independently of outside energy, without a battery, without a rechargeably battery or another power supply, and when a defined temperature is exceeded a generated voltage or current signal can be used for signaling or controlling subsequent actions. This further enables overload protective devices to be realized that trigger when the desired temperature is exceeded and e.g. effect the switching off of an apparatus or emit a fault signal. In particular in autonomous units that must function as long as possible such as all types of vehicles, in space etc.
The detector that is independent of outside energy can further be used to protect kitchen appliances such as deep fryers and other fat-heating devices.
This detector can also be used to safeguard and monitor thermal processes, furnaces, engines, vehicles, aircraft and ships and other mobile and stationary objects.
The invention can also be applied where fluid media are present such as in the food, chemical and petrochemical industries, the drinking water and service water supplies and in other areas of industry.
In an advantageous design the fluid medium is an extinguishing agent, e.g. water, a water foam mixture, a gas or a chemical extinguishing agent.
Since some extinguishing agents also have a cooling effect, the term extinguishing agent is further also understood to mean a coolant.
The valve can be used in extinguishing systems and extinguishing devices where pressure tanks, assemblies, pipes or volume segments with extinguishing agents or coolants are closed off by a valve that opens when needed, e.g. on detecting a fire, as a result of an electric voltage or a voltage signal and releases the flow of the extinguishing agent.
DE 199 45 856 B4 describes a sprinkler device having a valve that opens on predetermined criteria, this valve being controlled by a sensor that reacts fast to parameters that are generated in the case of a fire, multiple sensors being provided that control the valve by means of an evaluation algorithm and the sensors being capable of reacting to different parameters of the fire. In a particular design variant the document describes a glass tube where a piezoelectric behavior is used to trigger an alarm. The current is supplied by means of an electric line and a battery.
EP 0 824 027 A1 describes an explosion protection device having an electric release, the release device being operated using a spring and a solenoid. The solenoid is fed electricity continuously. As soon as the power supply for the solenoid fails the spring relaxes so that a locking device is retracted that acts on a further mechanism. The device does not operate independently of energy and also is not suited to be arranged on an extinguishing device.
US 2009/0301601 A1 uses a piezo igniter that generates a spark voltage by triggering a press button as is known from every lighter, using which a combustion process is started whose exhaust gases can be used for further processes.
US 2007/0215362 A1 describes a fire extinguishing system where a cover plate having a fusible link is arranged at a fire extinguishing nozzle. Using a piezoelectric switch an alarm can be triggered. When a certain temperature is exceeded, the fusible link melts and the cover plate of the sprinkler housing falls down, a switch triggering an alarm in the process. In this document a device called a piezoelectric switch is used, this in reality being a piezoelectric acoustic signal transmitter.
US 2011/0278029 A1 describes an independent self-releasing modular fire suppression unit that can be mounted to a ceiling. On a printed circuit board a piezo element is situated that is triggered by a smoke detector and triggers an acoustic signal. A glass tube is disposed on a printed circuit board on a tank lid that bursts in heat. The glass tube acts against a spring and a switch that triggers an alarm signal. Batteries are provided for supplying power to the device.
A disadvantage with this state of the art is that the detectors and valves existing in release devices require additional outside energy such as e.g. batteries, rechargeable batteries or other external power supplies required. Thus detectors require additional outside energy both in the state of readiness in which they always have to detect fire parameters when they arise, and also in the release state after a fire parameter has been detected. It is also valves such as e.g. solenoid valves that require additional outside energy for maintaining the state of readiness and/or the release state.